物理化学学报 >> 2014, Vol. 30 >> Issue (9): 1778-1786.doi: 10.3866/PKU.WHXB201407112

材料物理化学 上一篇    

氮掺杂石墨烯的制备及其对氧还原反应的电催化性能

彭三, 郭慧林, 亢晓峰   

  1. 西北大学化学与材料科学学院, 合成与天然功能分子化学教育部重点实验室, 西安 710069
  • 收稿日期:2014-05-15 修回日期:2014-07-10 发布日期:2014-08-29
  • 通讯作者: 郭慧林 E-mail:hlguo@nwu.edu.cn
  • 基金资助:

    国家自然科学基金(21175105,21375104),教育部高等学校博士学科点专项科研基金(20126101110015),陕西省自然科学基金(2014JM2042)和生命分析化学国家重点实验室开放基金(SKLACLS1210)资助项目

Preparation of Nitrogen-Doped Graphene and Its Electrocatalytic Activity for Oxygen Reduction Reaction

PENG San, GUO Hui-Lin, KANG Xiao-Feng   

  1. Key Laboratory of Synthetic and Natural Functional Molecule Chemistry Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, P. R. China
  • Received:2014-05-15 Revised:2014-07-10 Published:2014-08-29
  • Contact: GUO Hui-Lin E-mail:hlguo@nwu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21175105, 21375104), Specialized Research Fund for the Doctoral Program of Higher Education of China (20126101110015), Natural Science Foundation of Shaanxi Province, China (2014JM2042), and State Key Laboratory of Analytical Chemistry for Life Science, China (SKLACLS1210).

摘要:

以氧化石墨烯(GO)为原料、丙酮肟(DMKO)为还原剂和氮掺杂剂,采用化学还原法制备了不同氮掺杂含量的石墨烯(NG). 利用场发射透射电子显微镜(FETEM)、紫外-可见(UV-Vis)光谱、傅里叶变换红外(FTIR)光谱、X射线光电子能谱(XPS)、zeta 电位和纳米粒度分析、循环伏安(CV)和旋转圆盘电极(RDE)等手段对材料的形貌、结构、成分和电化学性质进行表征. 结果显示:DMKO能有效地还原GO,且通过调节GO与DMKO的质量比,可以得到不同还原效果的NG,其氮含量范围为4.40%-5.89%(原子分数);GO与DMKO的质量比为1:0.7时制备的氮掺杂石墨烯(NG-1)在O2饱和0.1 mol·L-1 KOH溶液中对氧还原反应(ORR)的电催化性能最佳,其ORR峰电流为0.93 mA·cm-2,电子转移数为3.6,这归因于其较高含量的吡啶-N增加了材料的ORR活性位点. 此外,石墨化-N由于其较高的电子导电性倾向于产生较高的氧还原峰电流,而吡啶-N较低的超电势倾向于产生较正的氧还原峰电位. 与商用Pt/C相比,该材料展现出了优异的抗CH3OH“跨界效应”的特性.

关键词: 石墨烯, 氮掺杂, 氧还原反应, 电催化

Abstract:

Nitrogen-doped graphene (NG) was prepared by chemical reduction of graphene oxide (GO) using dimethyl ketoxime (DMKO) as reducing and doping agents. The morphologies, structures, compositions, and electrocatalytic activities of the as-prepared materials were investigated using field-emission transmission electron microscopy (FETEM), ultraviolet- visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), zeta potential and nanoparticle analyses, cyclic voltammetry (CV), and the rotating disk electrode (RDE) method. The results showed that GO sheets were effectively reduced by DMKO. NG samples with different nitrogen contents were obtained by adjusting the mass ratio of GO to DMKO; the nitrogen contents were in the range 4.40%-5.89% (atomic fraction). NG-1, obtained using a GO/DMKO mass ratio of 1:0.7, showed excellent electrocatalytic activity in the oxygen reduction reaction (ORR) in an O2-saturated 0.1 mol·L-1 KOH solution. The peak current was 0.93 mA·cm-2, and the number of electrons transferred per O2 was 3.6; this was attributed to the increase in the number of ORR active sites in the presence of pyridinic-N. In addition, the electrocatalytic activity of NG was found to be dependent on the graphitic-N content, which determined the limiting current density, because of its higher electronic conductivity. The pyridinic-N content improved the onset potential, because of its lower overpotential for the ORR. NG therefore exhibited a high selectivity in the ORR, with good tolerance of methanol cross-over effects. It is therefore superior to commercial Pt/C catalysts.

Key words: Graphene, Nitrogen doping, Oxygen reduction reaction, Electrocatalysis

MSC2000: 

  • O646